U.S. patent number 10,242,567 [Application Number 15/564,945] was granted by the patent office on 2019-03-26 for traffic light and traffic light color identification system, and methods thereof.
This patent grant is currently assigned to BOE TECHNOLOGY GROUP CO., LTD.. The grantee listed for this patent is BOE TECHNOLOGY GROUP CO., LTD.. Invention is credited to Jian Gao, Yingyi Li, Kairan Liu.
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United States Patent |
10,242,567 |
Li , et al. |
March 26, 2019 |
Traffic light and traffic light color identification system, and
methods thereof
Abstract
Traffic light and traffic light color identification system, and
methods thereof are provided. A traffic light includes a control
unit, configured to generate a control command; a signal modulating
unit, configured to modulate an electrical signal based on the
control command and output a modulation signal having a modulation
frequency corresponding to a color of a signal light of the traffic
light; and a signal generating unit configured to control the
signal light of the traffic light and to transfer a signal to a
vehicle, based on the modulation signal.
Inventors: |
Li; Yingyi (Beijing,
CN), Gao; Jian (Beijing, CN), Liu;
Kairan (Beijing, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
BOE TECHNOLOGY GROUP CO., LTD. |
Beijing |
N/A |
CN |
|
|
Assignee: |
BOE TECHNOLOGY GROUP CO., LTD.
(Beijing, CN)
|
Family
ID: |
57493039 |
Appl.
No.: |
15/564,945 |
Filed: |
April 21, 2017 |
PCT
Filed: |
April 21, 2017 |
PCT No.: |
PCT/CN2017/081326 |
371(c)(1),(2),(4) Date: |
October 06, 2017 |
PCT
Pub. No.: |
WO2018/014616 |
PCT
Pub. Date: |
January 25, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180308352 A1 |
Oct 25, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 18, 2016 [CN] |
|
|
2016 1 0565934 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G08G
1/04 (20130101); G08G 1/095 (20130101); G08G
1/096783 (20130101); G08G 1/07 (20130101); G08G
1/096716 (20130101) |
Current International
Class: |
G08G
1/07 (20060101); G08G 1/095 (20060101); G08G
1/04 (20060101); G08G 1/0967 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1353404 |
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Jun 2002 |
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CN |
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2824178 |
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Oct 2006 |
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CN |
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1990936 |
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Jul 2007 |
|
CN |
|
101593436 |
|
Dec 2009 |
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CN |
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101783964 |
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Jul 2010 |
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CN |
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102610115 |
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Jul 2012 |
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CN |
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103886767 |
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Jun 2014 |
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CN |
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104363382 |
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Feb 2015 |
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CN |
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105469618 |
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Apr 2016 |
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CN |
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106205152 |
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Dec 2016 |
|
CN |
|
Other References
First Office Action in the Chinese Patent Application No.
201610565934.9, dated Apr. 3, 2018; English translation attached.
cited by applicant .
Visible communication for advanced driver assistant systems, Navin
Kumar et al., Conftele 2009-7th Conference on Telecommunications,
Dec. 31, 2009. cited by applicant .
International Search Report & Written Opinion dated Jun. 30,
2017, regarding PCT/CN2017/081326. cited by applicant.
|
Primary Examiner: Trieu; Van T
Attorney, Agent or Firm: Westerman, Hattori, Daniels &
Adrian, LLP
Claims
What is claimed is:
1. A method, comprising: generating a control command; modulating
an electrical signal based on the control command to provide a
modulation signal; outputting the modulation signal having a
modulation frequency corresponding to a color of a signal light of
the traffic light; modulating a current intensity of the signal
light such that a lowest current intensity is greater than 0,
wherein the lowest current intensity is about 1/3 to about 1/2 of a
highest current intensity of the signal light; and controlling the
signal light to transfer a signal based on the modulation signal
and receivable by a vehicle.
2. The method according to claim 1, wherein the signal transferred
to the vehicle is a light signal including a visible light
signal.
3. A method, comprising: generating a control command; modulating
an electrical signal based on the control command to provide a
modulation signal; outputting the modulation signal having a
modulation frequency corresponding to a color of a signal light of
the traffic light; and controlling the signal light to transfer a
signal based on the modulation signal and receivable by a vehicle,
wherein the signal light emits at a negative angle downwards to a
ground and with respect to a horizontal direction, and an absolute
value of the negative angle is greater than or equal to about
5.degree. and smaller than or equal to about 10.degree..
4. A method, comprising: generating a control command; modulating
an electrical signal based on the control command to provide a
modulation signal; outputting the modulation signal having a
modulation frequency corresponding to a color of a signal light of
the traffic light; controlling the signal light to transfer a
signal based on the modulation signal and receivable by a vehicle,
collecting the signal light; converting the signal light to the
electrical signal; obtaining the modulation frequency of the
electrical signal; and determining the color of the signal light
based on the modulation frequency of the electrical signal.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application is a national stage application under 35 U.S.C.
.sctn. 371 of International Application No. PCT/CN2017/081326,
filed Apr. 21, 2017, which claims priority to Chinese Patent
Application No. 201610565934.9, filed Jul. 18, 2016, the contents
of which are incorporated by reference in the entirety.
TECHNICAL FIELD
The present disclosure generally relates to the optical
communication technologies and, more particularly, to traffic light
and traffic light color identification system, and their
methods.
BACKGROUND
With the development of economy, traffic network expands in various
directions. A large number of privately-owned vehicles are used in
people's daily life. However, many people with color vision
deficiency cannot obtain a driver's license because of the
restrictions of traffic rules. Also, because of the color vision
deficiency or color blindness, these people encounter a lot of
inconvenience when walking on the streets.
In 2003, the Visible Light Communications Consortium (VLCC) was
founded. The VLCC has been widely promoting the use of flashing
light-emitting diode (LED) light sources for data transmission, to
implement visible light communication.
Compared to technologies such as cable communication and radio
frequency (RF) communication, visible light communication has at
least the following advantages. First, visible light communication
does not require application for a spectrum authentication. In the
field of communication, the available radio frequencies are already
quite limited. Visible light communication based on, e.g., LED,
does not have the frequency allocation problems in the radio
frequency communication, and is less susceptible to interferences.
Further, the spectral band of the communication signals used in the
visible light communication is often in the range of about 380 nm
to about 780 nm, which is safe to humans. The visible light
communication can thus be used in an environment such as hospitals,
and other places having strict requirements on electromagnetic
interferences. Further, visible light communication is often easy
to debug and easy to implement. In addition, visible light
communication is often less costly.
There are many types of color vision deficiencies, among which the
most common type is the red-green color blindness. In general,
people with color blindness are not able to accurately identify
traffic lights and the information delivered by the traffic lights.
Color blindness generally has two symptoms. One symptom is that the
patients confuse two different colors A and B. The patients may
think A and B are the same color. For example, a patient with
red-color blindness is not able to distinguish between red and dark
green. Another symptom is that, the patients are not able to sense
colors but can only sense different tones, i.e., different levels
of brightness and darkness.
Thus, a visible light communication means to provide a system for
identifying colors of traffic lights for those people with color
vision deficiencies is desired.
SUMMARY
One aspect of the present disclosure provides a traffic light. The
traffic light includes: a control unit, configured to generate a
control command; a signal modulating unit, configured to modulate
an electrical signal based on the control command and output a
modulation signal having a modulation frequency corresponding to a
color of a signal light of the traffic light; and a signal
generating unit configured to control the signal light of the
traffic light and to transfer a signal to a vehicle, based on the
modulation signal.
Optionally, the signal modulating unit is further configured to
modulate a current intensity of the signal light such that a lowest
current intensity is greater than 0.
Optionally, the signal modulating unit is further configured to
modulate the current intensity of the signal light using an
amplitude shift keying method.
Optionally, the lowest current intensity is about 1/3 to about 1/2
of a highest current intensity of the signal light.
Optionally, the signal light emits at a negative angle downwards to
a ground and with respect to a horizontal direction.
Optionally, an absolute value of the negative angle is greater than
or equal to about 5.degree. and smaller than or equal to about
10.degree..
Optionally, the signal transferred to the vehicle is a light signal
including a visible light signal.
Optionally, the signal is receivable by a signal demodulating unit
on the vehicle.
Another aspect of the present disclosure provides a traffic light
color identification system. The traffic light color identification
system includes: a light-signal collecting unit, configured to
collect a light signal and converting the light signal to an
electrical signal; a signal demodulating unit, configured to obtain
a modulation frequency of the electrical signal; and a playing
unit, configured to inform a color of the light signal, after an
identifying unit determines the color of the light signal based on
the modulation frequency of the electrical signal.
Optionally, the playing unit includes a display unit configured to
display at least one of text or a graphic based on the color
determined by the identifying unit.
Optionally, the playing unit includes a voice unit configured to
play back a voice based on the color determined by the identifying
unit.
Optionally, the light-signal collecting unit is mounted over a
headlight or a top of a vehicle.
Optionally, the light-signal collecting unit includes: a reflective
panel configured to reflect the light signal and expanding a light
region of the light signal, and an image collecting device
configured to collect the light signal in the light region and
converting the light signal to the electrical signal.
Optionally, the reflective panel includes a base panel and
scattering particles coated over the base panel.
Optionally, the light signal is a visible light signal.
Another aspect of the present disclosure provides a method by
generating a control command; modulating an electrical signal based
on the control command to provide a modulation signal; outputting
the modulation signal having a modulation frequency corresponding
to a color of a signal light of the traffic light; and controlling
the signal light to transfer a signal based on the modulation
signal and receivable by a vehicle.
Optionally, the method further includes: modulating a current
intensity of the signal light such that a lowest current intensity
is greater than 0. The lowest current intensity is about 1/3 to
about 1/2 of a highest current intensity of the signal light.
Optionally, the signal light emits at a negative angle downwards to
a ground and with respect to a horizontal direction, and an
absolute value of the negative angle is greater than or equal to
about 5.degree. and smaller than or equal to about 10.degree..
Optionally, the signal transferred to the vehicle is a light signal
including a visible light signal.
Optionally, the method further includes: collecting the light
signal; converting the light signal to the electrical signal;
obtaining the modulation frequency of the electrical signal; and
determining the color of the light signal based on the modulation
frequency of the electrical signal.
BRIEF DESCRIPTION OF THE FIGURES
The following drawings are merely examples for illustrative
purposes according to various disclosed embodiments and are not
intended to limit the scope of the present disclosure.
FIG. 1 illustrates exemplary traffic lights according to various
disclosed embodiments of the present disclosure;
FIGS. 2A-2C each illustrates current intensity in an exemplary
traffic light according to various disclosed embodiments of the
present disclosure;
FIG. 3 illustrates the light-emitting direction of an exemplary
traffic light according to various disclosed embodiments of the
present disclosure;
FIG. 4 illustrates an exemplary system for identifying colors of
traffic lights according to various disclosed embodiments of the
present disclosure;
FIG. 5 illustrates exemplary modulation information by an exemplary
signal demodulating unit according to various disclosed embodiments
of the present disclosure;
FIG. 6 illustrates another exemplary system for identifying colors
of traffic lights according to various disclosed embodiments of the
present disclosure;
FIG. 7 illustrates another exemplary system for identifying colors
of traffic lights according to various disclosed embodiments of the
present disclosure;
FIGS. 8A and 8B each illustrates an exemplary position of a
light-signal collecting unit in an exemplary system for identifying
colors of traffic lights according to various disclosed embodiments
of the present disclosure;
FIG. 9 illustrates an exemplary light-signal collecting unit in an
exemplary system for identifying colors of traffic lights according
to various disclosed embodiments of the present disclosure;
FIG. 10 illustrates an exemplary reflective panel in a light-signal
collecting unit according to various disclosed embodiments of the
present disclosure;
FIG. 11 illustrates an exemplary process to control traffic lights
according to various disclosed embodiments of the present
disclosure;
FIG. 12 illustrates an exemplary process to identify colors of
traffic lights according to various disclosed embodiments of the
present disclosure; and
FIG. 13 illustrates an exemplary block diagram of a control unit in
a system for identifying colors of traffic lights according to
various disclosed embodiments of the present disclosure.
DETAILED DESCRIPTION
Exemplary embodiments will now be described in detail with
reference to the drawings. It is to be noted that the following
descriptions of some embodiments are presented herein for purposes
of illustration and description only. It is not intended to be
exhaustive or to be limiting.
FIG. 1 illustrates the block diagram of an exemplary traffic light.
As shown in FIG. 1, the disclosed traffic light includes a control
unit 101, a signal modulating unit 102, and a signal generating
signal 103. The traffic light may include signal lights emitting
light of different colors, e.g., red, green, and yellow.
In various embodiments, a traffic information managing system may
send a control signal to the control unit 101 through a
communication network. The control unit 101 may generate a control
command based on the control signal for adjusting electrical
signals sent to the signal lights.
The signal modulating unit 102 may modulate frequencies of the
electrical signals sent to the signal lights based on the control
command, and output modulation signals of different frequencies.
The modulation signals of different frequencies may correspond to
signal lights of different colors.
The signal generating unit 103 may control signal lights of
different colors to emit light based on the modulation signals.
The disclosed traffic lights may modulate the frequencies of the
electrical signals sent to the signal lights such that the
modulation signals of different modulation frequencies may
correspond to signal lights of different colors. The present
disclosure may provide a traffic light that can be identified or
recognized by a color identification system, for people with color
vision deficiencies. Driving may be safer for those people.
In various embodiments, the signal generating unit 103 may include
LED lights with a high photoelectric conversion rate to generate a
signal that can be received by a vehicle. Such signal may be a
light signal, for example, including visible light signals of
different colors. Often, the signal generating unit 103 may include
a red LED signal light, a yellow LED signal light, and a green LED
signal light. The signal modulating unit 102 may modulate the
frequency of the electrical signal of a signal light, where the
frequency of the electrical signal represents a number of times the
traffic light flashes in 1 second. In various embodiments,
modulation signals of different frequencies may be generated such
that different modulation signals may correspond to signal lights
of different colors.
In another embodiment, the signal modulating unit 102 may also be
used to modulate the current intensities of the signal lights such
that the lowest current intensity is greater than zero. In various
embodiments, the modulating unit 102 may also use an amplitude
shift keying (ASK) method to modulate the current intensities of
the signal lights. Specifically, the ASK method may use data bits
to control the current intensity of an LED light so as to control
the brightness level of the LED light. When the data bit is 1, the
current intensity may be the highest and the LED light may have a
relatively high brightness level, i.e., appearing bright; and when
the data bit is 0, the current intensity may be the lowest and the
LED light may have a relatively low brightness level, i.e.,
appearing dark.
In the present disclosure, the ASK method is used to control the
amplitudes, i.e., the brightness levels of the LED lights, of the
light signals through modulating signals and controlling current
intensities. In various embodiments, a current intensity range may
correspond to a signal light having a certain color. For example,
the current intensity of the red LED signal light may be the
highest, the current intensity of the yellow LED signal light may
be moderate, and the current intensity of the green LED signal
light may be the lowest. In some embodiments, the lowest current
intensity may be about a third or about a half of the highest
current intensity.
FIGS. 2A, 2B, and 2C each illustrates the current intensity of a
signal light according to an exemplary embodiment. In FIGS. 2A, 2B,
and 2C, I represents the current intensity of an LED signal light,
and t represents time.
The brightness level of an LED signal light may be dependent on the
current intensity of the LED signal light. A higher current
intensity in an LED signal light may correspond to a higher
brightness level of the LED signal light. The brightness level of
an LED signal light may be an average brightness level during a
unit of time. For example, assume a duty cycle of the signal
modulation is about 50%. If the lowest current intensity of the
signal light is 0, as shown in FIG. 2A, the brightness level or
average brightness level of the LED signal light is about half of
the maximum brightness level at the highest current intensity. If
the lowest current intensity of the signal light is about one third
of the highest current intensity, as shown in FIG. 2B, the average
brightness level of the LED signal light may be about two third of
the maximum brightness level at the highest current intensity,
which is about 33% higher than the average brightness level in the
zero lowest current intensity situation illustrated in FIG. 2A.
Further, if the lowest current intensity of the signal light is
about one half of the highest current intensity, as shown in FIG.
2C, the average brightness level of the LED traffic light can be
about 50%, higher than the average brightness level in the zero
lowest current intensity situation illustrated in FIG. 2A.
In some embodiments, the lowest current intensity, after
modulation, may be higher than zero. Thus, when the brightness
level of the surroundings is high, the LED signal lights may still
have sufficient brightness levels such that a high contrast,
between the brightness levels of the LED signal lights and the
brightness level of the light source in the surroundings, may be
obtained. The intensities of the light signals emitted by the
signal lights may be improved, making it easier for a receiving
terminal, such as a vehicle or a device configured with the
vehicle, to collect the light signals.
FIG. 3 illustrates the light-emitting direction by a signal light
of the traffic light in one embodiment. As shown in FIG. 3, the
signal light has a height h above the ground, a lateral distance
between the receiving terminal and the signal light is x, and a
longitudinal distance between the receiving terminal and the signal
light is y. The distance d between the receiving terminal and the
traffic terminal may be calculated using equation: d= {square root
over (x.sup.2+y.sup.2+h.sup.2)}.
A greater distance d between the receiving terminal and the traffic
light may result in a greater difficulty to collect signals. When a
vehicle having the receiving terminal moves to location A shown in
FIG. 3, the distance d1 between the receiving terminal and the
signal light may be smaller than the distance d2 between the
receiving terminal and the traffic light when the vehicle is at
location B. The receiving terminal may receive or collect signals
when moving between location A and location B. The signal light may
emit light along the direction shown in FIG. 3, the light-emission
angle of the traffic light may be .beta.. When the distance between
the receiving terminal and the traffic light is smaller than d1, no
or little light may be incident on the receiving terminal, and the
receiving terminal may not be able to collect any signals.
Thus, to better collect light signals when the distance between the
receiving terminal and the traffic light is small, the
light-emitting direction of the disclosed traffic light may have a
preset negative angle .theta. in a direction downwards to the
ground and with respect to the horizontal direction. An absolute
value of the preset negative angle .theta. may be greater than or
equal to about 5.degree. and smaller than or equal to about
10.degree.. In various embodiments, the negative angle .theta.
between the light-emitting direction and the horizontal direction
should not be too large or too small. If the absolute value of the
negative angle .theta. is too large, the receiving terminal may not
be able to receive signals when the receiving terminal is far away
from the signal light. If the absolute value of the negative angle
.theta. is too small, the receiving terminal may not be able to
receive signals when the receiving terminal is too close to the
signal light.
FIG. 4 illustrates the block diagram of an exemplary traffic light
color identification system according to some embodiments of the
present disclosure. As shown in FIG. 4, the disclosed traffic light
color identification system includes a light-signal collecting unit
401, a signal demodulating unit 402, and an identifying unit 403.
The disclosed system or specifically, the light-signal collecting
unit 401 may be a receiving terminal.
The light-signal collecting unit 401 may collect a visible light
signal emitted by a signal light of a traffic light, such as one of
the exemplary traffic lights described above, and convert the
visible light signal to a corresponding electrical signal.
The light-signal collecting unit 401 may include a photoelectric
sensor. The light-signal collecting unit 401 may collect the
modulated visible light signal and covert the modulated visible
light signal to the corresponding electrical signal using the
photoelectric sensor.
The signal demodulating unit 402 may obtain the frequency of the
electrical signal corresponding to the visible light signal.
The identifying unit 403 may determine the color of the signal
light based on the frequency of the electrical signal corresponding
to the visible light signal.
Visible light signals of different colors, after modulation, may
correspond to electrical signals of different frequencies. Based on
the frequency of the electrical signal corresponding to a visible
light signal, obtained by the signal demodulating unit 402, the
identifying unit 403 may determine the color of the signal light
emitting the visible light signal.
The disclosed traffic light color identification system may collect
the visible light signal and demodulate the collected visible light
signal to the electrical signal corresponding to the visible light
signal. The disclosed system may determine the color of a signal
light based on the frequency of the electrical signal corresponding
to a light signal emitted by the signal light. The disclosed system
may thus identify the colors of the traffic light, providing a
means to accurately identify the colors of the traffic light for
those having color vision deficiencies.
In various embodiments, the traffic light color identification
system may include a playing unit configured to provide information
including a color of the light signal. For example, the playing
unit may include a display unit and/or a voice unit for informing
the color of the light signal.
FIG. 6 illustrates anther exemplary traffic light color
identification system according to the present disclosure. The
traffic light color identification system shown in FIG. 6 is
similar to the system shown in FIG. 4, except that the system shown
in FIG. 6 further includes a display unit 404.
The display unit 404 may display text or graphic corresponding to
the color of the signal light, based on the identification result
by the identifying unit 403. The disclosed traffic light color
identification system may display different kinds of text and
graphics for signal lights of different colors. For example, when
the identification result is the red LED signal light, the
corresponding text may be "red" and the corresponding graphic may
be "!". When the identification result is the yellow LED signal
light, the corresponding text may be "yellow" and the corresponding
graphic may be ".circleincircle.". When the identification result
is the green LED signal light, the corresponding text may be
"green" and the corresponding graphic may be "". In various
embodiments, the display unit 404 may be arranged on a rearview
mirror of a vehicle such that a driver may learn about the color of
the signal light through the text or graphic shown by the display
unit 404.
The disclosed traffic light color identification system may collect
the visible light signal and demodulate the collected visible light
signal to the electrical signal corresponding to the visible light
signal. The disclosed system may determine the color of the signal
light based on the frequency of the electrical signal corresponding
to the visible light signal emitted by the signal light. The
disclosed system may display the text or graphic corresponding to
the color of the signal light such that people having color
blindness may be able to determine the color of the signal
light.
FIG. 7 illustrates another exemplary traffic light color
identification system according to the present disclosure. The
traffic light color identification system shown in FIG. 7 is
similar to the system shown in FIG. 4, except that the system shown
in FIG. 7 further includes a voice unit 405.
The voice unit 405 may play back a voice message corresponding to
the color of the signal light based on the identification result by
the identifying unit 403.
The disclosed traffic light color identification system may collect
the visible light signal and demodulate the collected visible light
signal to the electrical signal corresponding to the visible light
signal. The disclosed system may determine the color of the signal
light based on the frequency of the electrical signal corresponding
to the visible light signal emitted by the signal light. The
disclosed system may play the voice message corresponding to the
identified color of the signal light such that people with color
blindness may determine the color of the signal light.
In an embodiment, the light-signal collecting unit 401 may collect
the visible light signal emitted by the traffic light and convert
the collected visible light signal to the corresponding electrical
signal. In various embodiments, the light-signal collecting unit
401 may be a camera with a rolling shutter, which can progressively
and sequentially expose the collected visible light signal. The LED
light emitting the visible light signal may flash constantly. An
imaging unit in the camera may convert the collected visible light
signal to a digitized electrical signal, and an image processing
unit in the camera may amplify and decode the electrical signal to
form an image.
An exemplary image taken by the camera is shown in FIG. 5. The
image includes the images of the three signal lights, i.e., the
red, green, and yellow signal lights. The image of one signal light
may include alternately-arranged bright strips and dark strips,
i.e., one bright strip being sandwiched by two dark strips and vice
versa. A bright strip indicates the LED light turns bright and a
dark strip indicates the LED light turns dark. The signal
demodulating unit 402 may demodulate the electrical signal
corresponding to the visible light signal collected by the
light-signal collecting unit 401. Exemplary demodulation
information is shown in FIG. 5, which includes a "1010 . . . 1"
string. The binary 1 indicates the LED appears bright and the
binary 0 indicates the LED appears dark. The signal demodulating
unit 402 may demodulate the visible light signal into a binary
code. Because signal lights of different colors may flash at
different frequencies, the signal demodulating unit 402 may obtain
the color of the signal light based on the binary code demodulated
from the electrical signal corresponding to the visible light
signal.
The demodulation of the electrical signal may correspond to the
embodiment described above in connection with FIGS. 2A-2C, in which
the ASK method is used to modulate the current intensities of the
signal lights. The signal demodulating unit 402 may demodulate the
electrical signal corresponding to the visible light signal
modulated using the ASK method and collected by the light-signal
collecting unit 401, to obtain the intensity of the electrical
signal. The identifying unit 403 may determine the color of the
signal light based on the intensity of the electrical signal.
Specifically, the color of a signal light may be determined based
on a correspondence relationship between current intensity ranges
and colors, where the correspondence relationship may be
predetermined. For example, when the current intensity is
relatively high, the identifying unit 403 may determine that the
red LED light is on. When the current intensity is medium, the
identifying unit 403 may determine that the yellow LED light is on.
When the current intensity is relatively low, the identifying unit
403 may determine that the green LED light is on.
In various embodiments, the light-signal collecting unit 401 may
also be mounted over a headlight of the vehicle, as shown in FIG.
8A, or over the top of the vehicle, as shown in FIG. 8B. The
specific location of the light-signal collecting unit 401 should
not be limited by the embodiments of the present disclosure.
In another embodiment of the present disclosure, as shown in FIG.
9, the light-signal collecting unit 401 includes a reflective panel
901 and an image collecting device 902.
The reflective panel 901 may reflect and expand a visible light
region of the signal light, and project the visible light region to
the image collecting device 902. The visible light region of the
signal light refers to the region the visible light signal emitted
by the signal light is incident on. In various embodiments, the
reflective panel 901 may be arranged in any suitable position. For
example, the reflective panel 901 may be mounted on a front
windshield of the vehicle.
The image collecting device 902 may collect the light or visible
light signal reflected by the light-reflecting region of the
reflective panel 901, and convert the collected visible light
signal to the electrical signal. In various embodiments, the image
collecting device 902 may be a camera with a rolling shutter. The
camera may progressively and sequentially expose the collected
visible light signal reflected by the reflective panel 901. An
imaging unit in the camera may convert the collected visible light
signal to a digitized electrical signal, amplify and decode the
electrical signal through an image processing unit to form an
image. Because the LED light emitting the visible light signal
flash constantly, the image obtained by the camera may have
alternately-arranged bright strips and dark strips. Bright strips
may indicate that the LED light appears bright, and dark strips may
indicate that the LED light appears dark.
The reflective panel arranged in the disclosed traffic light color
identification system may reflect the visible light signal emitted
by the traffic light and expand the visible light region to the
image collecting device such that the image collecting device does
not need to adjust the filming angle to capture the visible light
signals. Thus, the image collecting device may be fixed on the
vehicle.
Further, as shown in FIG. 10, the reflective panel 901 includes a
base panel 1001 and scattering particles 1002 coated over the base
panel 1001 for reflecting the visible light signals to the image
collecting device 902 by diffuse reflection. The scattering
particles 1002 over the base panel 1001 may reduce the mirror
reflection of the visible light signals emitted by the LED lights
and increase the visible light region of the traffic light. The
visible light signals may be reflected to the image collecting
device 902 for the image collecting device 902 to collect.
FIG. 11 illustrates an exemplary process for controlling the
traffic light. As shown in FIG. 11, at S101, a control command for
adjusting an electrical signal of the traffic light is generated
based on a control signal.
In various embodiments, a traffic information managing system may
send the control signal to the traffic light through a
communication network. The traffic light may generate the control
command based on the control signal, to control the signal light of
a corresponding color, e.g., red, to emit light. In the meantime,
the control command may also turn off the signal lights of other
colors, e.g., green and yellow.
At S1102, a frequency of the electrical signal of the traffic light
is adjusted based on the control command and a modulation signal of
a modulation frequency is outputted. Modulation signals of
different modulation frequencies may correspond to signal lights of
different colors.
In various embodiments, the modulation signals of different
modulation frequencies may be set such that the modulation signals
of different frequencies may correspond to signal lights of
different colors. For example, when the control command is
configured to control the red LED light to emit light, the
frequency of the electrical signal corresponding to the red LED
light may be modulated based on the control command, to output the
modulation signal corresponding to the red LED light.
At S1103, a signal light of a certain color is controlled to emit
light based on the modulation signal.
For example, when the modulation signal corresponding to the red
LED light is generated, the modulation signal may be used to
control the red LED light to emit light.
In some embodiments, the method for controlling the traffic light
may include modulating a current intensity of the signal light
using the ASK method. A correspondence relationship between current
intensity ranges and colors of the signal lights can be preset.
Specifically, the ASK method may use data bits to control the
current intensity of an LED light, so as to control the brightness
level of the LED light. In the present disclosure, the ASK method
may be used to control current intensities through modulation
signals, and amplitudes of visible light signals, i.e., brightness
levels of the LED lights, may thus be controlled. In various
embodiments, different current intensity ranges may correspond to
signal lights of different colors. For example, the current
intensity of the red LED signal light may be set to a relatively
high value, the current intensity of the yellow LED signal light
may be set to a moderate value, and the current intensity of the
green LED signal light may be set to a relatively low value.
FIG. 12 illustrates an exemplary process for identifying a color of
a traffic light. As shown in FIG. 12, at S1201, a visible light
signal emitted by a signal light of the traffic light is collected
and converted to a corresponding electrical signal.
In various embodiments, a camera with a rolling shutter may be used
to collect the visible light signal, and an imaging unit of the
camera may convert the visible light signal to the corresponding
electrical signal.
At S1202, a frequency of the electrical signal corresponding to the
visible light signal is obtained.
In various embodiments, because the signal light, which is an LED
light emitting the visible light signal, may flash constantly, the
image of the signal light obtained by the camera may include
alternately-arranged bright strips and dark strips. A bright strip
indicates that the LED light appears bright, and a dark strip
indicates that the LED light appears dark. Binary code may be used
to represent the status of the LED light. In one embodiment, binary
1 may represent that the LED turns bright, and the binary 0 may
represent that the LED turns dark. Thus, the binary code of the
visible light signal may be obtained. The frequency of the
electrical signal corresponding to the visible light signal may be
determined.
At S1203, a color of the signal light is determined based on the
frequency of the electrical signal corresponding to the visible
light signal.
In various embodiments, visible light signals of different colors,
after modulation, may correspond to electrical signals of different
frequencies. By obtaining the frequency of the electrical signal
corresponding to the visible light signal, the color of the signal
light emitting the visible light signal may be obtained.
In some embodiments, the method for identifying the color of
traffic light may include obtaining the intensity of the electrical
signal corresponding to the visible light signal, and determining
the color of the visible light signal based on the intensity of the
electrical signal. Specifically, corresponding to the ASK method
described in the process for controlling the traffic light, the
correspondence relationship between the current intensity ranges
and the signal lights of different colors may be determined in
advance. The color of the signal light may thus be determined
according to the correspondence relationship. For example, when the
current intensity is relatively high, it may be determined that the
red LED signal light is on. When the current intensity is moderate,
it may be determined that the yellow LED signal light is on. When
the current intensity is relatively low, it may be determined that
the green LED signal light is on.
The present disclosure provides a traffic light, a method for
controlling the traffic light, and a system and a method for
identifying a color of the traffic light. A collected visible light
signal may be modulated to form an electrical signal corresponding
to the visible light signal. The color of the traffic light may be
determined based on the frequency of the electrical signal
corresponding to the visible light. That is, the color of the
traffic light may be identified. The present disclosure may thus
provide a means to accurately identify the color of the traffic
light for the people having color vision deficiency.
For illustrative purposes, the signal lights of the traffic light
described in the present disclosure include LED lights. In various
other embodiments, the signal lights may also include other
suitable light sources capable of emitting visible light signals
having modulated frequencies. The specific type of light source
used in the traffic light should not be limited by the embodiments
of the present disclosure.
In certain embodiments, a traffic light may also emit a light
signal with a wavelength not in the visible range. The light signal
may be modulated and demodulated by the disclosed traffic light
color identification system such that the frequency of the light
signal can be obtained for identifying the color of the traffic
light.
In certain other embodiments, a traffic light may emit both a
visible light signal and a light signal having a wavelength
different from the visible light signal and is invisible to human
eyes. The disclosed traffic light color identification system may
also be able to obtain the frequency of the light signal. In this
case, the traffic light may only need to modulate the frequency of
the invisible light signal such that the brightness level of the
traffic light can remain unaffected.
FIG. 13 illustrates a block diagram of a control circuit 1300
corresponding to the control 101 in FIG. 1. The control circuit
1300 may be integrated in a traffic light or may be a separate
device. The control circuit 1300 may control various operations of
the traffic light and may implement the functions of at least one
of the control unit 101, the signal modulating unit 102, or the
signal generating unit 103.
The control circuit 1300 may receive, process, and execute commands
from a traffic information managing system. The control circuit
1300 may include any appropriately configured computer system. As
shown in FIG. 13, the control circuit 1300 includes a processor
1302, a random access memory (RAM) 1304, a read-only memory (ROM)
1306, a storage 1308, a display 1310, an input/output interface
1312, a database 1314, and a communication interface 1316. Other
components may be added to and certain components may be removed
from the control circuit 1300 without departing from the principles
of the disclosed embodiments.
The processor 1302 may include any appropriate type of general
purpose microprocessor, digital signal processor or
microcontroller, or application specific integrated circuit (ASIC).
The processor 1302 may execute sequences of computer program
instructions to perform various processes associated with the
control circuit 1300. Computer program instructions may be loaded
into the RAM 1304 for execution by the processor 1302 from the
read-only memory 1306, or from the storage 1308. The storage 1308
may include any appropriate type of mass storage provided to store
any type of information that the processor 1302 may need to perform
the processes. For example, the storage 1308 may include one or
more hard disk devices, optical disk devices, flash disks, or other
storage devices to provide storage space.
The display 1310 may provide information to a user or users of the
control circuit 1300, such as a maintenance technician of the
traffic light. The display 1310 may include any appropriate type of
computer display device or electronic device display (e.g., CRT or
LCD based devices). The input/output interface 1312 may be provided
for the user to input information into the control circuit 1300 or
for the user to receive information from the control circuit 1300.
For example, the input/output interface 1312 may include any
appropriate input device, such as a keyboard, a mouse, an
electronic tablet, voice communication devices, touch screens, or
any other optical or wireless input devices. Further, the
input/output interface 1312 may receive data from and/or send data
to other external devices.
Further, the database 1314 may include any type of commercial or
customized database, and may also include analysis tools for
analyzing the information in the databases. The communication
interface 1316 may provide communication connections such that the
control circuit 1300 may be accessed remotely and/or communicate
with other systems through computer networks or other communication
networks via various communication protocols, such as transmission
control protocol/internet protocol (TCP/IP), hypertext transfer
protocol (HTTP), etc.
In one embodiment, the control circuit 1300 may receive a control
signal from the traffic information managing system through the
communication interface 1316. The processor 1302 may generate a
control command for adjusting electrical signals of signal lights
of the traffic light. The processor 1302 may modulate the
frequencies of the electrical signals sent to the signal lights,
and may output modulation signals of different frequencies.
Modulation signals having different frequencies may correspond to
signal lights of different colors. The processor 1302 may output
the modulation signals to the signal lights through the
input/output interface 1312.
The control circuit 1300 may also be used in the disclosed traffic
light color identification system to control various operations of
the system. The control circuit 1300 may implement the functions of
at least one of the light-signal collecting unit 401, the signal
modulating unit 402, the identifying unit 403, the display unit
404, or the voice unit 405.
In one embodiment, the disclosed system may receive the visible
light signal emitted by a signal light through the input/output
1312, and the processor 1302 may convert the collected visible
light signal to a corresponding electrical signal. The processor
1302 may obtain the frequency of the electrical signal that
corresponds to the visible light signal, and determine the color of
the signal light based on the frequency of the electrical signal.
In some embodiments, the display 1310 may implement the functions
of the display unit 404, which displays the color of the signal
light. In some embodiments, the input/output interface 1312 may
implement the functions of the voice unit 405 to play back a voice
message corresponding to the color of the signal light so as to
inform the user of the color of the signal light.
In the present disclosure, the terms "comprise", "include", or any
other variant thereof are intended to encompass a non-exclusive
inclusion such that the process, method, article or device
comprising a series of elements includes not only those elements
but also other elements that are not explicitly listed, or those
that are inherent to such process, method, article, or device. In
the absence of more restrictions, the elements defined by the
statement "including a . . . " do not exclude the presence of
additional elements in the process, method, article, or device that
includes the elements. The orientation or positional relationship
indicated by the terms "up", "down", etc. is based on the azimuth
or positional relationship shown in the drawings and is only for
the purpose of describing the embodiments and simplifying the
description, rather than indicating or implying that the means or
elements have a specific orientation, or are constructed and
operated in a particular orientation. Thus, these terms are not
construed as limiting the disclosure. The terms "mount", "connect",
"link", and the like should be broadly understood. For example,
these terms may indicate a fixed connection, a detachable
connection, a one-piece connection, a mechanical connection, or an
electrical connection. These terms may also indicate direct
connection, indirect connection through intermediary, of internal
connection between two components. The specific meaning of the
above-mentioned terms in the present disclosure may be understood
by those skilled in the art in light of specific circumstances.
A number of specific details are set forth in the specification of
the present disclosure. It is to be understood, however, that
embodiments of the disclosure may be practiced without these
specific details. In some embodiments, well-known methods,
structures, and techniques have not been shown in detail so as not
to obscure the understanding of this specification. Similarly, it
should be understood that in order to simplify the present
disclosure and to assist in understanding one or more of the
various inventive aspects, features of the present disclosure are
sometimes grouped together into a single embodiment in the above
description of exemplary embodiments of the present disclosure, or
in the description of it. However, the disclosed method or device
should not be construed as reflecting the intent that the claimed
disclosure is more characteristic than the features clearly set
forth in each claim. More specifically, as reflected in the claims,
the inventive aspect can be less than all of the features of the
previously disclosed single embodiment. Accordingly, the claims
that follow the specific embodiments are expressly incorporated
into this particular embodiment, each of which is a separate
embodiment of the disclosure.
The foregoing description of the embodiments of the disclosure has
been presented for purposes of illustration and description. It is
not intended to be exhaustive or to limit the disclosure to the
precise form or to exemplary embodiments disclosed. Accordingly,
the foregoing description should be regarded as illustrative rather
than restrictive. Obviously, many modifications and variations will
be apparent to practitioners skilled in this art. The embodiments
are chosen and described in order to explain the principles of the
technology, with various modifications suitable to the particular
use or implementation contemplated. It is intended that the scope
of the disclosure be defined by the claims appended hereto and
their equivalents in which all terms are meant in their broadest
reasonable sense unless otherwise indicated. Therefore, the term
"the disclosure", "the present disclosure" or the like does not
necessarily limit the claim scope to a specific embodiment, and the
reference to exemplary embodiments of the disclosure does not imply
a limitation on the disclosure, and no such limitation is to be
inferred. Moreover, the claims may refer to "first", "second",
etc., followed by noun or element. Such terms should be understood
as a nomenclature and should not be construed as giving the
limitation on the number of the elements modified by such
nomenclature unless specific number has been given. Any advantages
and benefits described may not apply to all embodiments of the
disclosure. It should be appreciated that variations may be made to
the embodiments described by persons skilled in the art without
departing from the scope of the present disclosure as defined by
the following claims. Moreover, no element or component in the
present disclosure is intended to be dedicated to the public
regardless of whether the element or component is explicitly
recited in the following claims.
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